Finned tube boiler section



United States Patent Inventor Appl No. Filed Spencer E. Reynolds 3180Pinecrest Drive, Murrysville,

Pennsylvania 15668 804,421 March 5, 1969 "Patented Oct. 20, 1970FINNEDTUBE BOILER 'SECT ION 1 Claim, 1 Drawing Fig.

US. Cl 122/225, 122/ 367 Int. Cl F22b 23/00 Field of Search. 122/225,235, 367

' [56] References Cited 1 UNITED STATES PATENTS 2,454,866 1 1/1948Gallaher 122/225 3,242,910 3/1966 Hale 122/367X 3,302,705 2/1967 Witten122/235X Primary Examiner-Kenneth W. Sprague Attorney-William J. RuanoABSTRACT: A gas boiler fabricated section of sheet metal, finned tubeswhich is adapted to be stacked with identical sections, and wherein themetal tubes extend horizontally in spaced parallel relationship and arejoined at the ends by vertical inlet and outlet headers or pipes whichare held together by push nipples.

Patented Oct. 20, 1970 iii-ii INVENTOR. SPENCER E.REYNOLDS is ATTORNEYFig.4.

FINNEI) 'IUIIII BOILER SECTION This invention relates generally to heattransfer apparatus and, more particularly, to a finned tube gas boilersection adapted to be stacked and joined with identical sections forincreasing the heat transfer capacity of the assembly.

In gas boilers of well known construction, such as that shown in U.S.Pat. No. 2,918,043, assigned to the present assignee, heat transferunits are positioned immediately above the gas flame and water iscirculated through them.

An outstanding disadvantage of such heat transfer units is that they areof cast iron and are cast into an intricate construction, includingfins, therefore involve high manufacturing costs-also such fins do notcompletely encircle the cast iron water conthiits, whereby heat transferefficiency is decreased.

An object of the presentinvcntion is 16 prof/idea fabricated, sheetmetal, finned tube boiler section which is devoid of the abovenameddisadvantages and which is relatively easy and inexpensive tomanufacture.

A further object of the present invention is to provide finned tubesections for gas boilers and the like which has high heat transferefficiency and which can be very easily and quickly stacked togetherwith selective numbers of identical sections for providing selectiveheat capacity of the entire assembly.

A still more specific object of the invention is to provide a finnedtube, gas boiler section which is made of sheet metal, such as steel ofthin gauge, and wherein the tubing is cylindrical and completelysurrounded by fins, and wherein the inlet and outlet header passages maybe easily attached together with identical units by means of pushnipples to increase the overall capacity of the assembly.

Other object and advantages will become more apparent from a study ofthe following description, taken with the accompanying drawing wherein:

FIG. 1 is an elevational view of one of the finned tube gas boiler sstqtis mlqqs he p ssnt nysm FIG. 2 is a vertical, cross-sectional viewtaken along line II-II of FIG. 1', l

FIG. 3 is a fragmentary, sectional view taken along line ll-l" ff 1; a d

FIG. 4 is an end view in elevation, and partially in cross section,showing how identical units of the construction shown in FIG. 1 arejoined together.

Referring more particularly to FIG. 1 of the drawing, numeral Igenerally denotes a finned tube, gas boiler section constructed inaccordance with the principles of the present invention, which sectioncomprises a plurality of sheet metal cylindrical tubes 3, preferably ofthin gauge steel such as 2 inch diameter tubes of. l2 inch thickness.

Tubes 3 are each completely surrounded by spirally wound, continuousfins 4, such as those inch high, about .065 inch thick end of a densityof 3 fins per inch adhered to the outer surface of the tubing, such asby spot welding or the like. The right end of said tubes or tubing 3, asviewed in FIG. 1 is connected to a vertically extending, inlet pipe orheader 2 having an end cap 7 and which is welded to an inlet pipe 5,extending at right angles thereto and connected through connection 6 toan inlet source of water.

Header 2 may be 2- /2 inches in diameter. A suitable length of tubes is32 inches, although it should be understood that this dimension as wellas the aforesaid dimensions may be varied. The left ends of tubes 3 areconnected to an outlet, vertically extending header or pipe 2, ofhollow, cylindrical construction whose top end is welded to ahorizontally extending pipe 5 having a tapered connection 6 to an outletfor the water and whose bottom end is capped.

As shown more clearly in FIG. 2, the outlet header or pipe 5 (as well asthe inlet pipe 5) is reamed on both end portions 6 at an angle of about3 from the horizontal for receiving push nipples 10, as shown moreclearly in FIG. 4, having a corresponding external taper so as to form awatertight joint with the reamed surface 6 of pipe 5 of an adjoiningsection. While only two sections are shown joined together in FIG, 4, itwill be readily apparent that any number of sections may be stackedtogether and joined by push nipples, such as 10, at both the inlet andoutlet headers 5, so as to selectively increase or decrease the overallcapacity of the heat exchange assembly.

Thus it will be seen that I have provided a highly efficient, finnedtube gas boiler section of sheet metal, such as steel, wherein the tubesconnecting the headers are cylindrical and completely encircled byspirally wound fins so as to increase the heat transfer capacity aboutthree fold compared to that of cast iron tubes of known construction,and where identical sections are provided to enable stacking of anyselective number of sections to provide a heat transfer assembly of anydesired heat transfer capacity; also I have provided a gas boilersection having a capacity of at least l20,000 B.t.u. per section whichis increased to 240,000 B.t.u. for two sections, etc. and which mayoperate at pressures within the range of to 750 lbs. per square inch;also I have provided a heat transfer section which is very easily andcheaply manufactured and yet which has exceptionally high heat transfercapacity.

While I have illustrated and described a single specific embodiment ofmy invention, it will be understood that this is by way of illustrationonly and that various changes and modifications may be made within thecontemplation of my invention and within the scope ofthe followingclaim.

I claim:

I. A fabricated boiler section adapted to be stacked and joined togetherwith an identical boiler section for gas boilers and the like,comprising a plurality of hollow, cylindrical sheet metal tubes inspaced parallel relationship and in substantially a common plane, eachof said tubes being completely surrounded by continuous spirally woundfins, inlet and outlet header pipes joining together the respective endsof said tubes to provide inlet and outlet connections for flowing fluidthrough said tubes. each header pipe being internally tapered outwardlyat both end sections. and push nipples of cylindrical, tubular outlinewith correspondingly tapered outer surfaces joining said taperedportions of said header pipes in fluid-tight relationship to enable aselective number of identical boiler sections to be joined together toform a complete heat transfer assembly.

